Camera.java

package com.pandadev.eyecandy.graphics;

import org.lwjgl.util.vector.Matrix4f;
import org.lwjgl.util.vector.Vector3f;

import com.pandadev.eyecandy.MatrixStack;

public abstract class Camera {
    private final Vector3f position = new Vector3f();
    private final Vector3f target = new Vector3f(0f, 0f, -1f);
    private final Vector3f up = new Vector3f(0f, 1f, 0f);

    public abstract void update(float delta);

    public void applyTransformations(){
        Matrix4f viewMatrix = new Matrix4f();
        Vector3f zAxis = getForward();
        Vector3f xAxis = getRight();
        Vector3f yAxis = getUp();
        viewMatrix.m00 = xAxis.x;
        viewMatrix.m10 = xAxis.y;
        viewMatrix.m20 = xAxis.z;
        viewMatrix.m01 = yAxis.x;
        viewMatrix.m11 = yAxis.y;
        viewMatrix.m21 = yAxis.z;
        viewMatrix.m02 = zAxis.x;
        viewMatrix.m12 = zAxis.y;
        viewMatrix.m22 = zAxis.z;
        viewMatrix.m03 = position.x;
        viewMatrix.m13 = position.y;
        viewMatrix.m23 = position.z;
        MatrixStack.getViewMatrix().load(viewMatrix);
    }

    public Vector3f getForward(){
        Vector3f forward = new Vector3f();
        Vector3f.sub(position, target, forward);
        forward.normalise();
        return forward;
    }

    public Vector3f getBackward(){
        Vector3f backward = getForward();
        backward.negate();
        return backward;
    }

    public Vector3f getRight(){
        Vector3f right = new Vector3f();
        Vector3f.cross(getForward(), up, right);
        return right;
    }

    public Vector3f getLeft(){
        Vector3f left = getRight();
        left.negate();
        return left;
    }

    public Vector3f getUp(){
        Vector3f up = new Vector3f();
        Vector3f.cross(getForward(), getRight(), up);
        return up;
    }

    public Vector3f getDown(){
        Vector3f down = getUp();
        down.negate();
        return down;
    }

    public Vector3f getPosition(){
        return position;
    }

    public Vector3f getTarget(){
        return target;
    }

    public void setPosition(Vector3f position){
        this.position.set(position);
    }

    public void setTarget(Vector3f target){
        this.target.set(target);
    }
}